Investigating the electrical behavior of nanoparticle infused holes on carbon fiber reinforced composites during fatigue loading
Abstract
One of the major problems and engineering issues in aircraft and automotive industries is
galvanic corrosion on metal-metal and metal-composite interfaces. This occurs when two
dissimilar metals or alloys are connected to each other at a common interface. Two metals, such
as a carbon fiber-reinforced composite (CFRC) and a steel alloy, when joined together,
experience galvanic corrosion at the joined interfaces because the difference in their electrical
potentials and the presence of electrolytes or moisture causes the generation of galvanic cells.
Carbon fiber being more noble than other metals and having excellent electric conductivity
corrodes slowly. Therefore, the metals or alloys attached to a CFRC on an aircraft, automobile,
or other structure corrode faster, and the resulting corrosion weakens the structural integrity of
the composites. This thesis provides a detailed study of the mitigation of galvanic corrosion and
improvement of corrosion resistance on a composite-metal joined structure. The experiments
executed here were based on the application of 2, 4, and 8 weight percentages of nanoparticles
(nanoclay and nanotalc) on a carbon fiber-reinforced composite hole having a baseline
composition of epoxy resin (LOCTITE EA 9394). The composite specimens were treated with
the nanoparticles and subjected to cyclic tensile loads on a MTS 810 test machine to investigate
the variation of electrical resistance with respect to applied loads and time. The plots of
resistance vs load and plots of resistance vs time mostly show an upward trend, indicating that
with the application of nanoparticles as a sealant between two composite structures, the
resistance to corrosion and deformation is increased, thereby decreasing the corrosive current
throughout the composite surface. Nanoclay particles displayed a better performance, with the
highest resistance measured at 43.9 ohms with the application of 8% wt% nanoclay particles.
Description
Thesis(M.S) - Wichita State University, College of Engineering, Dept. of Mechanical Engineering